OS - Part 3

Any mechanism for controlling access of processes or users to resources defined by the OS

Defense of the system against internal and external attacks

Allows user to change to effective ID with more rights

Allows operating systems to run applications within other Oses

used when source CPU type different from target type (i.e. PowerPC to Intel x86)

When computer language not compiled to native code

OS natively compiled for CPU, running guest OSes also natively compiled

VMM

provides virtualization services

Collection of separate, possibly heterogeneous, systems networked together